drivers/serial/clps711x.c

   1 /*
   2  *  linux/drivers/char/clps711x.c
   3  *
   4  *  Driver for CLPS711x serial ports
   5  *
   6  *  Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
   7  *
   8  *  Copyright 1999 ARM Limited
   9  *  Copyright (C) 2000 Deep Blue Solutions Ltd.
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation; either version 2 of the License, or
  14  * (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  * GNU General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License
  22  * along with this program; if not, write to the Free Software
  23  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  24  */
  25
  26 #if defined(CONFIG_SERIAL_CLPS711X_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
  27 #define SUPPORT_SYSRQ
  28 #endif
  29
  30 #include <linux/module.h>
  31 #include <linux/ioport.h>
  32 #include <linux/init.h>
  33 #include <linux/console.h>
  34 #include <linux/sysrq.h>
  35 #include <linux/spinlock.h>
  36 #include <linux/device.h>
  37 #include <linux/tty.h>
  38 #include <linux/tty_flip.h>
  39 #include <linux/serial_core.h>
  40 #include <linux/serial.h>
  41 #include <linux/io.h>
  42
  43 #include <mach/hardware.h>
  44 #include <asm/irq.h>
  45 #include <asm/hardware/clps7111.h>
  46
  47 #define UART_NR         2
  48
  49 #define SERIAL_CLPS711X_MAJOR   204
  50 #define SERIAL_CLPS711X_MINOR   40
  51 #define SERIAL_CLPS711X_NR      UART_NR
  52
  53 /*
  54  * We use the relevant SYSCON register as a base address for these ports.
  55  */
  56 #define UBRLCR(port)            ((port)->iobase + UBRLCR1 - SYSCON1)
  57 #define UARTDR(port)            ((port)->iobase + UARTDR1 - SYSCON1)
  58 #define SYSFLG(port)            ((port)->iobase + SYSFLG1 - SYSCON1)
  59 #define SYSCON(port)            ((port)->iobase + SYSCON1 - SYSCON1)
  60
  61 #define TX_IRQ(port)            ((port)->irq)
  62 #define RX_IRQ(port)            ((port)->irq + 1)
  63
  64 #define UART_ANY_ERR            (UARTDR_FRMERR | UARTDR_PARERR | UARTDR_OVERR)
  65
  66 #define tx_enabled(port)        ((port)->unused[0])
  67
  68 static void clps711xuart_stop_tx(struct uart_port *port)
  69 {
  70         if (tx_enabled(port)) {
  71                 disable_irq(TX_IRQ(port));
  72                 tx_enabled(port) = 0;
  73         }
  74 }
  75
  76 static void clps711xuart_start_tx(struct uart_port *port)
  77 {
  78         if (!tx_enabled(port)) {
  79                 enable_irq(TX_IRQ(port));
  80                 tx_enabled(port) = 1;
  81         }
  82 }
  83
  84 static void clps711xuart_stop_rx(struct uart_port *port)
  85 {
  86         disable_irq(RX_IRQ(port));
  87 }
  88
  89 static void clps711xuart_enable_ms(struct uart_port *port)
  90 {
  91 }
  92
  93 static irqreturn_t clps711xuart_int_rx(int irq, void *dev_id)
  94 {
  95         struct uart_port *port = dev_id;
  96         struct tty_struct *tty = port->info->port.tty;
  97         unsigned int status, ch, flg;
  98
  99         status = clps_readl(SYSFLG(port));
 100         while (!(status & SYSFLG_URXFE)) {
 101                 ch = clps_readl(UARTDR(port));
 102
 103                 port->icount.rx++;
 104
 105                 flg = TTY_NORMAL;
 106
 107                 /*
 108                  * Note that the error handling code is
 109                  * out of the main execution path
 110                  */
 111                 if (unlikely(ch & UART_ANY_ERR)) {
 112                         if (ch & UARTDR_PARERR)
 113                                 port->icount.parity++;
 114                         else if (ch & UARTDR_FRMERR)
 115                                 port->icount.frame++;
 116                         if (ch & UARTDR_OVERR)
 117                                 port->icount.overrun++;
 118
 119                         ch &= port->read_status_mask;
 120
 121                         if (ch & UARTDR_PARERR)
 122                                 flg = TTY_PARITY;
 123                         else if (ch & UARTDR_FRMERR)
 124                                 flg = TTY_FRAME;
 125
 126 #ifdef SUPPORT_SYSRQ
 127                         port->sysrq = 0;
 128 #endif
 129                 }
 130
 131                 if (uart_handle_sysrq_char(port, ch))
 132                         goto ignore_char;
 133
 134                 /*
 135                  * CHECK: does overrun affect the current character?
 136                  * ASSUMPTION: it does not.
 137                  */
 138                 uart_insert_char(port, ch, UARTDR_OVERR, ch, flg);
 139
 140         ignore_char:
 141                 status = clps_readl(SYSFLG(port));
 142         }
 143         tty_flip_buffer_push(tty);
 144         return IRQ_HANDLED;
 145 }
 146
 147 static irqreturn_t clps711xuart_int_tx(int irq, void *dev_id)
 148 {
 149         struct uart_port *port = dev_id;
 150         struct circ_buf *xmit = &port->info->xmit;
 151         int count;
 152
 153         if (port->x_char) {
 154                 clps_writel(port->x_char, UARTDR(port));
 155                 port->icount.tx++;
 156                 port->x_char = 0;
 157                 return IRQ_HANDLED;
 158         }
 159         if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
 160                 clps711xuart_stop_tx(port);
 161                 return IRQ_HANDLED;
 162         }
 163
 164         count = port->fifosize >> 1;
 165         do {
 166                 clps_writel(xmit->buf[xmit->tail], UARTDR(port));
 167                 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
 168                 port->icount.tx++;
 169                 if (uart_circ_empty(xmit))
 170                         break;
 171         } while (--count > 0);
 172
 173         if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
 174                 uart_write_wakeup(port);
 175
 176         if (uart_circ_empty(xmit))
 177                 clps711xuart_stop_tx(port);
 178
 179         return IRQ_HANDLED;
 180 }
 181
 182 static unsigned int clps711xuart_tx_empty(struct uart_port *port)
 183 {
 184         unsigned int status = clps_readl(SYSFLG(port));
 185         return status & SYSFLG_UBUSY ? 0 : TIOCSER_TEMT;
 186 }
 187
 188 static unsigned int clps711xuart_get_mctrl(struct uart_port *port)
 189 {
 190         unsigned int port_addr;
 191         unsigned int result = 0;
 192         unsigned int status;
 193
 194         port_addr = SYSFLG(port);
 195         if (port_addr == SYSFLG1) {
 196                 status = clps_readl(SYSFLG1);
 197                 if (status & SYSFLG1_DCD)
 198                         result |= TIOCM_CAR;
 199                 if (status & SYSFLG1_DSR)
 200                         result |= TIOCM_DSR;
 201                 if (status & SYSFLG1_CTS)
 202                         result |= TIOCM_CTS;
 203         }
 204
 205         return result;
 206 }
 207
 208 static void
 209 clps711xuart_set_mctrl_null(struct uart_port *port, unsigned int mctrl)
 210 {
 211 }
 212
 213 static void clps711xuart_break_ctl(struct uart_port *port, int break_state)
 214 {
 215         unsigned long flags;
 216         unsigned int ubrlcr;
 217
 218         spin_lock_irqsave(&port->lock, flags);
 219         ubrlcr = clps_readl(UBRLCR(port));
 220         if (break_state == -1)
 221                 ubrlcr |= UBRLCR_BREAK;
 222         else
 223                 ubrlcr &= ~UBRLCR_BREAK;
 224         clps_writel(ubrlcr, UBRLCR(port));
 225         spin_unlock_irqrestore(&port->lock, flags);
 226 }
 227
 228 static int clps711xuart_startup(struct uart_port *port)
 229 {
 230         unsigned int syscon;
 231         int retval;
 232
 233         tx_enabled(port) = 1;
 234
 235         /*
 236          * Allocate the IRQs
 237          */
 238         retval = request_irq(TX_IRQ(port), clps711xuart_int_tx, 0,
 239                              "clps711xuart_tx", port);
 240         if (retval)
 241                 return retval;
 242
 243         retval = request_irq(RX_IRQ(port), clps711xuart_int_rx, 0,
 244                              "clps711xuart_rx", port);
 245         if (retval) {
 246                 free_irq(TX_IRQ(port), port);
 247                 return retval;
 248         }
 249
 250         /*
 251          * enable the port
 252          */
 253         syscon = clps_readl(SYSCON(port));
 254         syscon |= SYSCON_UARTEN;
 255         clps_writel(syscon, SYSCON(port));
 256
 257         return 0;
 258 }
 259
 260 static void clps711xuart_shutdown(struct uart_port *port)
 261 {
 262         unsigned int ubrlcr, syscon;
 263
 264         /*
 265          * Free the interrupt
 266          */
 267         free_irq(TX_IRQ(port), port);   /* TX interrupt */
 268         free_irq(RX_IRQ(port), port);   /* RX interrupt */
 269
 270         /*
 271          * disable the port
 272          */
 273         syscon = clps_readl(SYSCON(port));
 274         syscon &= ~SYSCON_UARTEN;
 275         clps_writel(syscon, SYSCON(port));
 276
 277         /*
 278          * disable break condition and fifos
 279          */
 280         ubrlcr = clps_readl(UBRLCR(port));
 281         ubrlcr &= ~(UBRLCR_FIFOEN | UBRLCR_BREAK);
 282         clps_writel(ubrlcr, UBRLCR(port));
 283 }
 284
 285 static void
 286 clps711xuart_set_termios(struct uart_port *port, struct ktermios *termios,
 287                          struct ktermios *old)
 288 {
 289         unsigned int ubrlcr, baud, quot;
 290         unsigned long flags;
 291
 292         /*
 293          * We don't implement CREAD.
 294          */
 295         termios->c_cflag |= CREAD;
 296
 297         /*
 298          * Ask the core to calculate the divisor for us.
 299          */
 300         baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk/16);
 301         quot = uart_get_divisor(port, baud);
 302
 303         switch (termios->c_cflag & CSIZE) {
 304         case CS5:
 305                 ubrlcr = UBRLCR_WRDLEN5;
 306                 break;
 307         case CS6:
 308                 ubrlcr = UBRLCR_WRDLEN6;
 309                 break;
 310         case CS7:
 311                 ubrlcr = UBRLCR_WRDLEN7;
 312                 break;
 313         default: // CS8
 314                 ubrlcr = UBRLCR_WRDLEN8;
 315                 break;
 316         }
 317         if (termios->c_cflag & CSTOPB)
 318                 ubrlcr |= UBRLCR_XSTOP;
 319         if (termios->c_cflag & PARENB) {
 320                 ubrlcr |= UBRLCR_PRTEN;
 321                 if (!(termios->c_cflag & PARODD))
 322                         ubrlcr |= UBRLCR_EVENPRT;
 323         }
 324         if (port->fifosize > 1)
 325                 ubrlcr |= UBRLCR_FIFOEN;
 326
 327         spin_lock_irqsave(&port->lock, flags);
 328
 329         /*
 330          * Update the per-port timeout.
 331          */
 332         uart_update_timeout(port, termios->c_cflag, baud);
 333
 334         port->read_status_mask = UARTDR_OVERR;
 335         if (termios->c_iflag & INPCK)
 336                 port->read_status_mask |= UARTDR_PARERR | UARTDR_FRMERR;
 337
 338         /*
 339          * Characters to ignore
 340          */
 341         port->ignore_status_mask = 0;
 342         if (termios->c_iflag & IGNPAR)
 343                 port->ignore_status_mask |= UARTDR_FRMERR | UARTDR_PARERR;
 344         if (termios->c_iflag & IGNBRK) {
 345                 /*
 346                  * If we're ignoring parity and break indicators,
 347                  * ignore overruns to (for real raw support).
 348                  */
 349                 if (termios->c_iflag & IGNPAR)
 350                         port->ignore_status_mask |= UARTDR_OVERR;
 351         }
 352
 353         quot -= 1;
 354
 355         clps_writel(ubrlcr | quot, UBRLCR(port));
 356
 357         spin_unlock_irqrestore(&port->lock, flags);
 358 }
 359
 360 static const char *clps711xuart_type(struct uart_port *port)
 361 {
 362         return port->type == PORT_CLPS711X ? "CLPS711x" : NULL;
 363 }
 364
 365 /*
 366  * Configure/autoconfigure the port.
 367  */
 368 static void clps711xuart_config_port(struct uart_port *port, int flags)
 369 {
 370         if (flags & UART_CONFIG_TYPE)
 371                 port->type = PORT_CLPS711X;
 372 }
 373
 374 static void clps711xuart_release_port(struct uart_port *port)
 375 {
 376 }
 377
 378 static int clps711xuart_request_port(struct uart_port *port)
 379 {
 380         return 0;
 381 }
 382
 383 static struct uart_ops clps711x_pops = {
 384         .tx_empty       = clps711xuart_tx_empty,
 385         .set_mctrl      = clps711xuart_set_mctrl_null,
 386         .get_mctrl      = clps711xuart_get_mctrl,
 387         .stop_tx        = clps711xuart_stop_tx,
 388         .start_tx       = clps711xuart_start_tx,
 389         .stop_rx        = clps711xuart_stop_rx,
 390         .enable_ms      = clps711xuart_enable_ms,
 391         .break_ctl      = clps711xuart_break_ctl,
 392         .startup        = clps711xuart_startup,
 393         .shutdown       = clps711xuart_shutdown,
 394         .set_termios    = clps711xuart_set_termios,
 395         .type           = clps711xuart_type,
 396         .config_port    = clps711xuart_config_port,
 397         .release_port   = clps711xuart_release_port,
 398         .request_port   = clps711xuart_request_port,
 399 };
 400
 401 static struct uart_port clps711x_ports[UART_NR] = {
 402         {
 403                 .iobase         = SYSCON1,
 404                 .irq            = IRQ_UTXINT1, /* IRQ_URXINT1, IRQ_UMSINT */
 405                 .uartclk        = 3686400,
 406                 .fifosize       = 16,
 407                 .ops            = &clps711x_pops,
 408                 .line           = 0,
 409                 .flags          = UPF_BOOT_AUTOCONF,
 410         },
 411         {
 412                 .iobase         = SYSCON2,
 413                 .irq            = IRQ_UTXINT2, /* IRQ_URXINT2 */
 414                 .uartclk        = 3686400,
 415                 .fifosize       = 16,
 416                 .ops            = &clps711x_pops,
 417                 .line           = 1,
 418                 .flags          = UPF_BOOT_AUTOCONF,
 419         }
 420 };
 421
 422 #ifdef CONFIG_SERIAL_CLPS711X_CONSOLE
 423 static void clps711xuart_console_putchar(struct uart_port *port, int ch)
 424 {
 425         while (clps_readl(SYSFLG(port)) & SYSFLG_UTXFF)
 426                 barrier();
 427         clps_writel(ch, UARTDR(port));
 428 }
 429
 430 /*
 431  *      Print a string to the serial port trying not to disturb
 432  *      any possible real use of the port...
 433  *
 434  *      The console_lock must be held when we get here.
 435  *
 436  *      Note that this is called with interrupts already disabled
 437  */
 438 static void
 439 clps711xuart_console_write(struct console *co, const char *s,
 440                            unsigned int count)
 441 {
 442         struct uart_port *port = clps711x_ports + co->index;
 443         unsigned int status, syscon;
 444
 445         /*
 446          *      Ensure that the port is enabled.
 447          */
 448         syscon = clps_readl(SYSCON(port));
 449         clps_writel(syscon | SYSCON_UARTEN, SYSCON(port));
 450
 451         uart_console_write(port, s, count, clps711xuart_console_putchar);
 452
 453         /*
 454          *      Finally, wait for transmitter to become empty
 455          *      and restore the uart state.
 456          */
 457         do {
 458                 status = clps_readl(SYSFLG(port));
 459         } while (status & SYSFLG_UBUSY);
 460
 461         clps_writel(syscon, SYSCON(port));
 462 }
 463
 464 static void __init
 465 clps711xuart_console_get_options(struct uart_port *port, int *baud,
 466                                  int *parity, int *bits)
 467 {
 468         if (clps_readl(SYSCON(port)) & SYSCON_UARTEN) {
 469                 unsigned int ubrlcr, quot;
 470
 471                 ubrlcr = clps_readl(UBRLCR(port));
 472
 473                 *parity = 'n';
 474                 if (ubrlcr & UBRLCR_PRTEN) {
 475                         if (ubrlcr & UBRLCR_EVENPRT)
 476                                 *parity = 'e';
 477                         else
 478                                 *parity = 'o';
 479                 }
 480
 481                 if ((ubrlcr & UBRLCR_WRDLEN_MASK) == UBRLCR_WRDLEN7)
 482                         *bits = 7;
 483                 else
 484                         *bits = 8;
 485
 486                 quot = ubrlcr & UBRLCR_BAUD_MASK;
 487                 *baud = port->uartclk / (16 * (quot + 1));
 488         }
 489 }
 490
 491 static int __init clps711xuart_console_setup(struct console *co, char *options)
 492 {
 493         struct uart_port *port;
 494         int baud = 38400;
 495         int bits = 8;
 496         int parity = 'n';
 497         int flow = 'n';
 498
 499         /*
 500          * Check whether an invalid uart number has been specified, and
 501          * if so, search for the first available port that does have
 502          * console support.
 503          */
 504         port = uart_get_console(clps711x_ports, UART_NR, co);
 505
 506         if (options)
 507                 uart_parse_options(options, &baud, &parity, &bits, &flow);
 508         else
 509                 clps711xuart_console_get_options(port, &baud, &parity, &bits);
 510
 511         return uart_set_options(port, co, baud, parity, bits, flow);
 512 }
 513
 514 static struct uart_driver clps711x_reg;
 515 static struct console clps711x_console = {
 516         .name           = "ttyCL",
 517         .write          = clps711xuart_console_write,
 518         .device         = uart_console_device,
 519         .setup          = clps711xuart_console_setup,
 520         .flags          = CON_PRINTBUFFER,
 521         .index          = -1,
 522         .data           = &clps711x_reg,
 523 };
 524
 525 static int __init clps711xuart_console_init(void)
 526 {
 527         register_console(&clps711x_console);
 528         return 0;
 529 }
 530 console_initcall(clps711xuart_console_init);
 531
 532 #define CLPS711X_CONSOLE        &clps711x_console
 533 #else
 534 #define CLPS711X_CONSOLE        NULL
 535 #endif
 536
 537 static struct uart_driver clps711x_reg = {
 538         .driver_name            = "ttyCL",
 539         .dev_name               = "ttyCL",
 540         .major                  = SERIAL_CLPS711X_MAJOR,
 541         .minor                  = SERIAL_CLPS711X_MINOR,
 542         .nr                     = UART_NR,
 543
 544         .cons                   = CLPS711X_CONSOLE,
 545 };
 546
 547 static int __init clps711xuart_init(void)
 548 {
 549         int ret, i;
 550
 551         printk(KERN_INFO "Serial: CLPS711x driver\n");
 552
 553         ret = uart_register_driver(&clps711x_reg);
 554         if (ret)
 555                 return ret;
 556
 557         for (i = 0; i < UART_NR; i++)
 558                 uart_add_one_port(&clps711x_reg, &clps711x_ports[i]);
 559
 560         return 0;
 561 }
 562
 563 static void __exit clps711xuart_exit(void)
 564 {
 565         int i;
 566
 567         for (i = 0; i < UART_NR; i++)
 568                 uart_remove_one_port(&clps711x_reg, &clps711x_ports[i]);
 569
 570         uart_unregister_driver(&clps711x_reg);
 571 }
 572
 573 module_init(clps711xuart_init);
 574 module_exit(clps711xuart_exit);
 575
 576 MODULE_AUTHOR("Deep Blue Solutions Ltd");
 577 MODULE_DESCRIPTION("CLPS-711x generic serial driver");
 578 MODULE_LICENSE("GPL");
 579 MODULE_ALIAS_CHARDEV(SERIAL_CLPS711X_MAJOR, SERIAL_CLPS711X_MINOR);